US2013108A - Production of carboxylic amides - Google Patents

Description

of aluminium, thor um', tungsten, cerium, praseo- Patented Sept. 3,1935

PATENT. OFFICE i 2,013,168 Pnonoorron OVFVCARBOXYLIC AMIDES r Walter epne and Ernst Keyssner, Ludwigshafen- 1 on-the- Rhinc, Germany, assignors to I. G. Farbenindustrie Aktiengesellschaft, Frankfort-oni the-Main, Germany Drawing- Applicafion, ess, 1933, Serial f No. 678,056. In German J 6;1932

Claims. 01. 260-124) a; The present inventionrelates to the production of amides of higher fatty acids." 1 .Itis wellkno-wnthat the amides of higher fatty acids :containing more than about 10. carbon 1 atomscontrasted with the amides of lower fatty acids arej'only obtainablewith difficulty bythe action of gaseous, ammonia on the fatty .acids. Thus hitherto ;the employment of pressure with the higher fatty acids, has, been indispensable. Moreover, there is a danger, especially when heatingfor longperiodsof time, thatathe amide may,

be converted into the ;corresponding nitrile by the splitting oif of water. i

We have now found that amides of higher fatty acids can bejobtained in good yields without the employment of pressure by passing gaseous ammonia at temperatures between the meltingpoint ofthe fatty acids and 250C. through the fused fatty acids in the presence of-a solid, inorganic substance having a large superficial area which are designated in the art as surface catalysts. Said solid, inorganic substances comprise for example aluminium hydrosilicates such as-bleach ing earths, such as fullersearth,si1ica 'geL'naturaI.

or artificial zeolites, porous oxides and phosphates dymium, neodymium and lanthanium, or bauxite, active carbon and pumice which is preferably impregnated withacids, such as phosphoric, sulphuric or boric acids or acid salts, such as primary sodium or potassium sulphate. The

, said solid, inorganic substances are usually employed in an amount of between about 1 and about 20, preferably between about 2 and about 5, per cent by Weight of the fatty acids. 7

The reaction may be carried out in a vertical tower, the gaseous ammonia being preferably led inat the bottom of said tower. When working with large batches of acids it is preferable to preheat the ammonia to about the temperature. of the fused acid.

The ammonia is preferably employed in a practically dry state; when the unconsumed gas is refluxed, it is preferable to dry it before returning it into the reaction vessel, for example with calcined lime. The gas stream is usually led through the molten acids at the ratio of from 5 to of the reaction and to lower said velocity in the proportion that less ammonia is consumed. It is preferable to work at temperatures between 150 and 180 C. ,When employing higher temperatures up to 300 C., the speed of formation of the amide is certainly increased, but atthe same time the conversion of the amide formed into the corresponding nitrile commences, the reaction being also influenced bythe period of working and the lauric, myristic, p alinitic, 'margaric, cerotic,

inontam'c, melissic, myricylic, oleic, elaidic, erucic,

'linoleic, linolenic, hydroxystearic and ricinoleic acids. Most valuable amides are obtained from stearic and oleic acid, and especially from crude fatty acids obtainable fromfatty oils and fats,

especially of vegetable origin,for example coconut oil fatty acids, linseed oil fatty acids, cotton seed oil fatty acids, soya "bean -oil fatty acids, sunflower .oil fatty acids and the like.

The following examples will further illustrate the nature of this invention but the invention is not ,restrictedto these examples. The parts are by weight. e V i I Example 1 i 300 parts of stearic acid and 6 parts of granules of commercial silica gel of from 1 to 4 millimetres, diameter are heated tofrom 150 to 170 C. in a reaction vessel provided with an efiicient stirring device and an inletand outlet for theammonia to be employed. While stirring well, dry gaseous ammonia is led into the melt. After about 48 hours, the fatty aeid is almost completely converted into its amide. The resulting crude stearic amide may be employed as such or may be purified by working it with a solvent in which the stearic amide issoluble with difficulty, such as benzine or ligroin, whereby it is freed from small amounts of coloured impurities and any nitrile present, or by distillation in vacuo. The unabsorbed ammonia, which is withdrawn together with the water formed during the reaction may be freedfrom water by coo-ling or by treatment with water-extracting agents, and returned to the reaction vessel.

The procedure is similar with other higher fatty acids as for example coconut oil fatty acids, oleic acid, dihydroxystearic acid or the fatty 27 per cent after 6 hours 13 per cent after 12 hours 4.2 per cent after 24 hours 0.5 per cent after 48 hours In the case of pure palmitic acid the quantity of free acid present is 15.9 per cent after '7 hours 4.4 per cent after 12 hours 1.0 per cent after 24 hours 0.2 per cent after 48 hours Example 2 Crude ricinoleic acid, containing 62.9 per cent of free acid, is treated with gaseous ammonia in the manner described in Example 1. The quantity of free acid present is 6.3 per cent after 21 hours 2.9 per cent after hours 0.1 per cent after hours 1 The resulting salve-like products have a nitrogen content of 2.07 per cent.

What we claim is: V

1. The process for the production of amides of fatty acids containing more than 10 carbon atoms which comprises passing gaseous ammonia,

through a melt of the fatty acids, at a temperature between the melting point of the fatty acid and about 250 C. in the presence of a surface catalyst which is distributed in said melt.

2. The process for the production of amides of fatty acids containing more than 10 carbon atoms which comprises passing gaseous ammonia through a melt of the fatty acids, at a temperature between about and about C. in the presence of a surface catalyst which is distributed in said melt.

3. The process for the production of amides of fatty acids containing more than 10 carbon atoms which comprises passing. gaseous ammonia through a melt of the fatty acids, at a temperature between about 150 and about 180 C. in the presence of a surface catalyst which is distributed in said melt, the unabsorbed ammonia being freed from the water formed during the reaction and repassed through the melt.

4. The process for the production of amides of fatty acids containing more than 10 carbon atoms which comprises passing gaseous ammonia through a melt of the fatty acids, at a temperature between the melting point of the fatty acids and about 250 C. in the presence of silica gel.

5. The process for the production of amides of fatty acids containing more than 10 carbon atoms which comprises passing gaseous ammonia through a melt of the fatty acids at a temperature between about 150 and about 180 C. in the presence of silica gel.

6. The process for the production of stearic amide which comprises passing gaseous ammonia at between about 150 and about 180 C. through a melt of stearic acid in the presence of silica gel.

7. The process for the production of stearic amide which comprises passing gaseous ammonia at between about 150 and about 180 C. through a melt of stearic acid in the presence of silica gel, the unabsorbed ammonia being freed from the water formed during the reaction and repassed through the melt.

8. The process for the production of amides of fatty acids containing more than 10 carbon atoms which comprises passing gaseous ammonia through a melt of fatty acids obtainable from fatty oils and fats, at a temperature between about 150 and about 180 C. in the presence of a surface catalyst which is distributed in said melt. 9. The process for the production of amides of fatty acids containing more than 10 carbon atoms which comprises passing gaseous ammonia through a melt of fatty acids obtainable from fatty oils and fats of vegetable origin, at a temperature between about 150 and about 180 C. in the presence of a surface catalyst which is distributed in said melt.

10. The process for the production of amides of fatty acids containing more than 10 carbon atoms which comprises passing gaseous ammonia through a melt of coconut oil fatty acids, at a temperature between about 150 and about 180 C. in the presence of a surface catalyst which is distributed in said melt.

' WALTER REPPE.

ERNST KEYSSNER.